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Harnessing Wind Energy in Eritrea

Eritrea's development of efficient and affordable renewable energy, particularly of wind-powered and solar energy, has contributed tremendously to the lives of Eritrea's rural heartland and coastal communities.

In 2007, at a cost of 4 million Nakfa, Eritrea's first wind-powered electric generators were installed by Vergnet company in Assab. As a result of the success achieved in Assab, other parts of the Southern Red Sea region, including Edi, Berasole, Beilul, Gahro and Rahaita were introduced to wind turbines by the same company. While conventional windmills have three blades, Vergent Company has two blades that allows it to have the same efficiency but with lower maintenance cost.

According to the head of renewable energy department, the 3 large windmills installed in Assab have the capacity to each generate 250 kilowatts of electricity, while the smaller turbines in the other towns can generate up to 30 Kilowatts. Since installment, reports have indicated fuel dependency in that region have reduced by 10% and in Assab alone wind-powered energy meets 20% of the city's electric consumption.

High wind velocity in Eritrea's Southern Red Sea region has become a great resource to harness renewable clean energy. In order for windmills to produce sufficient electricity, wind speeds of 7 knots (8 mph; 13km) or more are required. Wind speeds in the Southern Red Sea region regularly reach 10 knots (11mph; 18km ) and more, making any future wind turbine development in that region an excellent investment.

The Government of Eritrea has disclosed their goals are to invest more on wind energy till 50 percent of the nation's grid electricity comes from using wind turbines.

8 comments:

How come they are two blades? I mean you already have the stand, and all you have to add is another 5-10% cost to make them three blades. Sometimes, I do not understand why the heck people do what they do. I think the stand can support a three blade fan rather than to have only two blade who takes more wind to start the engine.

What you are saying does not make sense. Three blades can generate more energy than two blades, three blades has the potential to generate more power out of soft wind than two blades would against relatively stronger wind. You can see the science of what I am saying very easily, have a paper with two sides and three sides fold and look at which rotates faster and lasts longer. As a child I used to play a game called helicopter, where we design a three or four blade curved cyclone looking wind conveyor, which pushes the blades fast and the transfer of power from one blade to another is so visible for the naked eye. I also remember making two blade helicopter, and they do not generate lots of wind RPS (rotation per second) occasionally the wind energy distributed between the two cyclone folds blades them out to create static, while friends get lots of rotation on their three and four blades. There were times I have seen older kids designing six cyclone processor and takes more energy to get some rotation, but in times of high wind it rotates for an extended period. However given the weight and material cost as well as the area wind, I am convinced three blades would be more effective, even if they are to cost more than 10% of the total expense, because they can increase power generation if not by 30% more, they will bring a good 20%+ additional power. Which will mean more money conversion down the road.

Anonymous of August 8, the writer of this article is correct, as is anonymous #2, two blades are indeed better than three. The company that made Eritrea's wind turbines is Vergnet. Here's what they have to say on this matter.

"All Vergnet wind turbines are 2-blade. Why? A 2-blade rotor is lighter, easier to install and easier to tilt down for maintenance or for hurricane protection. Being able to tilt them down allows them to be serviced easily and quickly on the ground, without hoisting equipment, for the 20-year lifetime of the turbine.

In fact, the amount of power produced does not depend on the number of blades but on the rotor swept area, and therefore on the rotor diameter. Consequently, a 2-blade rotor harnesses as much wind energy as a 3-blade rotor of the same diameter.

Rotating-hub technology which Vergnet has been improving for 20 years, and incorporating the latest technological advances in the aeronautics industry (helicopter rotors), allows the forces exerted on the structure to be considerably reduced. Drive train and structural elements are consequently much lighter and more durable over time."